Well I just had a chance to go over my logs for the past few months and the spammers are at it again. As most, more alert, webmasters are no doubt aware one of the newer tactics of the evil spammers is to use whats known as referral spam. Thier hope is that a site woudl ahve their stats up and wiewable to the public, and therefore give them a better ranking in search engines by littering the innocent webhosts site with links to their spamvertised site. As soon as I saw it in my logs I knew what I shoudl do, but rather than reinvent the wheel I did some google searchign and found the most common method for dealing with this is to use the apache SetEnvIfNoCase module to match keywords on the referrer and then deny the hit. This gives them a 403 forbidden error and should cut down on the massive amounts of traffic I’ve been seeing. I hate these loosers…
One great tool I did come across to test the rule is mentioned in the following post:
http://www.daveschalkboard.com/index.php/archives/2004/07/13/wannabrowser-http-user-agent-spoofing/
It was a godsend to test my rules out. I liked it so much I even donated $5.
John's Musings 
WannaBrowser stopped working for me. I found an extension for Firefox that pretty much does the same thing. It’s called RefSpoof.
As to referral spamming. Good luck with the .htaccess thing. I fought with that for a few months. However, I got so frustrated entering in new entries in there, that I just gave up on the whole thing. I have yet to find a way of defeating them. It’s like trying to defeat email spam. You can get close, but once you find something that seems to work, they come up with another method and defeat the ones you have so far.